This invention relates to electronic devices, and is more particularly concerned with an electronic key-like device containing an electronic circuit, and a receptacle for receiving the device and establishing electrical contact with the electronic circuit. The invention also concerns commodity metering systems, particularly electricity metering systems, employing such devices and receptacles.
In our United Kingdom patent application No. 8401932 (Publication No. 2153573A), there is described and claimed a prepayment electricity metering system in which an electronic key containing a memory co-operates with a receptacle in an electricity meter to control the supply of electricity to a consumer. Prior art electronic keys suitable for use in such a context are typically designed to be used in a manner similar to that in which a conventional mechanical key is used, i.e., they are designed to be inserted into the receptacle, and then turned (or rotated) in the receptacle to establish the required electrical contact. Although this has the merit of being familiar to, and therefore readily understandable by, consumers using electronic keys for the first time, it has the disadvantage that the key and receptacle are mechanically more complex, and therefore more expensive to make, than is strictly necessary.
It is one object of the present invention to provide an electronic key-like device and receptacle which are relatively simple and inexpensive to manufacture on a mass production basis, while still easy to use.
It is a further object of the present invention to provide a commodity metering system based on such an electronic key-like device and receptacle and having enhanced facilities.